VIM TIPS & TRICKS

Replace α=ß with α = ß

Got it! If α and ß are variables (i.e., any characters), and you want to replace occurrences of X=Y (where X and Y can be any characters) with X = Y (i.e., adding a space around the = sign), but leave X = Y as is, you can use the following Vim command:

:%s/\(\S\)=\(\S\)/\1 = \2/g

Explanation:

• :%s applies the substitution across all lines in the file.
• \(\S\) matches a non-whitespace character (the variable X).
• = matches the equal sign.
• \(\S\) matches another non-whitespace character (the variable Y).
• \1 and \2 are backreferences to the characters matched by the first and second \(\S\) groups, respectively.
• \1 = \2 replaces the matched text with the first and second characters with spaces around the equal sign.
• The g flag ensures the replacement happens globally on each line.

Example:

Before:

α=ß
var1=var2
a=b
α = ß

After running the command:

α = ß
var1 = var2
a = b
α = ß

This command will add a space around the equals sign ( =) only when there is no space already.

Delete everything after the occurrence of a certain keyword till end

Here’s how to do it:

1. Open the file in Vim.
2. Enter command mode by pressing Esc.
3. Type the following command to remove lines containing AND | and everything after it:

:%s/AND \|.*//g

Explanation:

• :%s tells Vim to perform the search and replace on all lines in the file (% means all lines).
• AND \| matches the literal string “AND |“. The backslash \ escapes the pipe symbol (|) to treat it as a literal character.
• .* matches everything following “AND |“.
• //g tells Vim to replace the matched text with nothing (i.e., delete it).

If you want to remove only the content following AND | and keep the rest of the line intact, you can use:

:%s/AND \|.*//g

This will remove the part starting from AND | till the end of the line without removing the whole line.

Remove lines not containing a pattern

%v/pattern/d

scroll simultaneously in 2 windows

:windo set scrollbind

Undo the scrollbind

:windo set noscrollbind

Toggle the scrollbind

:windo set scrollbind!